Should I install skylights?

If you have a dark area of you house and would like it lit up during the day, the usual way is to consider installing a skylight. However, with a skylight costing from $200 to $1000, is this the "best" way to do it these days? I think not.

Consider the cheapest option - $200 (and that's just for the hardware - you have to install yourself). How much electricity could this buy?

In WA, electricity costs 26c per unit. So $200 would buy about 800 units.

How much electricity does a light globe use? These days we should all be buying very efficient LED globes. I now use 7Watt globes for all my lighting. In a corridor or stairway you might only need 5W but let's assume a 10W globe. A 10W globe, left on for 10hours (ie all daylight hours) would use 100Watt hours which is 1/10th of a kWh or 0.1 unit. So you could run this globe for 8000 days or 22 years on $200 worth of electricity!

You could say but then the skylight is using natural power - no fuel burning. So buy Natural Power from Synergy and you can still run the globe for 15 years. If you have a solar power system, leaving the light on all day will hardly use any of your generated energy - 0.1units. So it's still a solar powered light source, just without all that plastic and cutting holes in your roof and ceiling.

You can buy "solar skylights" which as a kit using a dedicated solar panel, with wires down from the roof to a light globe, but again these cost several hundred dollars. I think just turning the light on is a better option.

The days of skylights are over.

Alan Benn

Based on a blog post first written by Alan Benn for Environment House 11/10/2015